Instead, in the six weeks since Ryan became the GOP vice presidential nominee — and particularly in the three weeks since the Republican National Convention — there has been mounting concern among Republicans that the pick has made Ryan look more like Romney — vague, cautious and limited to preset talking points.

Dissatisfaction with the trajectory of the campaign seems highest among Ryan’s most ardent backers. They view Romney’s campaign as having doubled back to a cautious strategy, avoiding Ryan’s trademark big ideas, and hoping President Obama will beat himself.

“I was wrong. When Paul Ryan was picked, I really thought this meant that the Romney campaign was shifting gears and was going to have a debate about big issues,” said Michael Tanner, an expert on health care and the budget at the libertarian Cato Institute.

He said that Romney’s campaign had previously cast the race as a referendum on Obama instead of as a choice between two clear visions. That hasn’t changed, he said.

“Why do you pick somebody like Paul Ryan if you’re going to run a referendum, Obama’s-done-a-bad-job campaign?” Tanner asked.

The dissatisfaction is not within Washington alone. Last week, Wisconsin Gov. Scott Walker (R) — who was so moved during Ryan’s GOP convention speech that he wept as his longtime ally spoke — told radio host Charlie Sykes that he thinks Ryan is not being used to his full potential.

“I just haven’t seen that kind of passion I know that Paul has transferred over to our nominee,” he said. He suggested that “pushback from some of the folks in the national campaign” might be restraining Ryan.

Asked about Walker’s critique on Friday, Ryan told reporters that he is “absolutely” satisfied with his role in the campaign.

“Look at what we’re doing,” he said during a stop at a fruit stand in Bartow, Fla. “We’re talking to local people, going around the country talking to local press. I’m excited about my role and I feel very comfortable with it.”

Part of Ryan’s predicament is the result of the strategic decisions of the Romney campaign, which some critics argue has been too cautious in its deployment of the seven-term Wisconsin Republican. There’s also the matter of some of Ryan’s self-inflicted wounds in recent weeks, as well as the substance of what he talks about on the campaign trail.

In his month-and-a-half as GOP vice presidential nominee, Ryan has not held a formal media availability with the dozen or so reporters that comprise his traveling press corps. He also did not hold any formal news conferences during his low-key return to Capitol Hill earlier this month or during his brief trip to Washington last week.

What Ryan has done is target local media outlets: He has sat down for more than 100 local TV or print interviews in 12 swing states, according to a Washington Post tally.

Some of those interviews have included tough questions. Last Tuesday, for instance, one reporter devoted an entire five-minute exchange to pressing Ryan on damaging remarks Romney made at a closed-door fundraiser in May. But many interviewers have lobbed softball questions at Ryan on issues that include his exercise routine and his affinity for health food.

In addition, the candidate — who often reminds voters that he has held more than 500 town hall events since entering office — has taken questions from attendees at only four of about three-dozen solo campaign events as the No. 2 on the GOP ticket.

Campaign aides disputed the notion that Ryan has been deployed cautiously, noting that he has done more than 20 national TV interviews, including a “60 Minutes” sit-down with Romney.

The campaign has sought to make the most of Ryan’s Midwestern roots by dispatching him to battlegrounds such as his home state of Wisconsin, where he has held two solo events; Iowa, where he has headlined four rallies; and Ohio, where he has held half a dozen events and will meet up with Romney on a bus tour this week.

In those states — as well as in Virginia and Florida, two other battlegrounds he visits frequently — Ryan works to woo blue-collar voters in part by making note of Obama’s 2008 remark about voters who “cling to their guns and religion.”

Ryan’s impact has been hampered by unforced errors, such as the one he made last month when he misstated his marathon time in an interview with conservative radio host Hugh Hewitt — a misstep that has so become part of Ryan’s national profile that it was lampooned in the season premiere of “Saturday Night Live.”

Then there’s the issue of the candidate’s campaign-trail remarks, in which caution has been Ryan’s watchword.

His stump speech, to which he tends to hew closely, is less a display of the budgetary know-how that has made him a darling of conservatives than it is an echo of Romney’s criticism of Obama on the economy, punctuated by anecdotes appealing to blue-collar, Midwestern voters that could just as easily be delivered by Tim Pawlenty or Rob Portman as by Ryan.

It’s not that Ryan hasn’t cast the election as a choice. He is fond of telling crowds, as he did in Newport News, Va., last week, that “it’s not just enough for us to criticize the terrible record; we owe you solutions.” He and Romney, he told the audience full of supporters, are offering voters “a very specific path, a real clear choice of two futures.”

And it’s not that Ryan is neglecting to cite the need to focus on big problems. Aside from his first week on the trail, during which he barely mentioned his signature plan to overhaul Medicare, he has raised the issue at the majority of his roughly three-dozen campaign stops as GOP vice presidential nominee, including in his appearance on Friday at AARP’s annual summit, at which he received a mixed reception.

Rather, the concern among some of the seven-term Wisconsin congressman’s supporters is that nowadays Ryan’s discussion of the big issues facing the country offers more specifics on what Obama has done wrong than what Romney and Ryan would do right.

“When a challenger merely appeals to disappointment with the incumbent and tries to reassure voters he’s not too bad an alternative, that isn’t generally a formula for victory,” he wrote. “Mike Dukakis lost.”

On the American Spectator’s blog last Wednesday, Ross Kaminsky, a Heartland Institute senior fellow and Denver-based conservative radio host, wrote that although it’s “refreshing” to see Ryan making his case to voters, “it is frustrating because Mitt Romney can’t seem to grasp the Ryan magic, and voters tend to put little emphasis on the running mate in their voting decisions.”

Some of Ryan’s top backers say that the Romney campaign could be doing more to underline Ryan’s strengths and help him break through what they consider an unhelpful mainstream media.

At Americans for Tax Reform, for instance, anti-tax activist Grover Norquist counseled a bold move by the campaign: having Ryan show up in Chicago to condemn the recent teachers’ strike to offer new ideas for reforming education spending.

“Yes, you can” break through, Norquist said in an interview. “But it’s not what you say. It’s got to be along the lines of showing up in Chicago.”

A Ryan spokesman disputed the notion that the campaign has not delivered on its promise to home in on the big ideas, noting that Ryan frequently mentions Medicare, tax reform and balancing the budget.

“Only one ticket has had the courage to talk about solutions to the big challenges facing America,” spokesman Brendan Buck said.

A Romney aide also defended the campaign’s decision to focus on local media, arguing that “this election is going to be won in eight, nine, 10, 11, you-name-it, states.”

“And so we’re traveling there, and we’re doing five, six, seven, eight local TV interviews every day. . . . So, it’s not surprising that someone in D.C. isn’t hearing him talk about Medicare and balancing the budget because his interview only aired in Colorado Springs,” said the aide, who spoke on the condition of anonymity to candidly discuss campaign strategy.

Despite the complaints from some top fans, other supporters of the Wisconsin congressman say that it’s unfair to have expected him to single-handedly elevate the election-year debate.

Rep. Trey Gowdy (R-S.C.), an ally of Ryan’s who saw the congressman during his recent visits to Capitol Hill, said there simply isn’t time for Ryan to lay out the complexities of his ideas in a stump speech. He argued that Ryan was doing it right by incorporating a few sentences, but few specifics, on the debt and deficit — and then moving on to other issues that Romney talks about.

“You get a short story — you get a sonnet, a haiku — when you’re on the stump,” Gowdy said. “You don’t get a treatise.”